When you see the Apple logo press and hold the Home button until it turns off. After that press and hold VolUp + Power until you see again the Apple logo. When you see it just let the Power button but keep pressing the VolUp . If you do it right you must have a working iphone again ;)
There are too ways to solve it. Method 1(you already tried): Try Reseting Network Settings by going into Settings>General>Reset>Reset Network Settings Your phone will restart deleting wifi passwords and so on. Method 2: If it's a hardware problem then the only solution is to heat the baseband ic (under sim tray) with a hairdryer for approximetely 5 mins According to iPhone could not be restored unknown error 1 Do not try to Restore phone via itunes cause your phone will be unusable (happened to me) Post back with the results